Engine-starting apparatus



Se t. 6 192 7 G. w. ELSEY ENGINE STARTING APPARATUS Filed May 6 PatentedSept. 6, 1927.

UNITED STATES PATENT OFFICE.

GEORGE W. ELSEY, OI ANDERSON, INDIANA, ASSIGNOR, BY HESNE ASSIGNMENTS,TO DELCO-REIY CORPORATION, 01 DAYTON, OHIO, A CORPORATION OF DELAWARE.

ENGINE-STARTING APPARATUS.

Application filed an a,

This invention relates to apparatus for starting an internal combustionengine, and particularly to the type of engine starter which includes anelectric motor havin a shaft connected through a one-way engaging clutchwith a pinion'adapted to move endwise into engagement with the gear ofan en 'ne to be started. t is among'the objects of the inventlon tosimplify the construction andreduce the cost of manufacture ofenginestarting apparatus of the type referred to.

Further objects and advantages of the resent invention will be apparentfrom the lbllowing description, reference being had to the accompanyingdrawings, wherem a preferred form of the pnesent ,invention is I clearlyshown.

In the drawings: Fig. 1 is a fragmentary longitudinal sec- 7 tional viewof the engine starting apparatus than Fig. 1.

In the drawing, 20 designates the field frame of an electric motor whichis controlled by a switch 21 mounted on the frame, and which includes anarmature 22 rotatable upon a shaft 23. The shaft 23 is sup rted by abearing (not shown) attached 0 the field frame 20, and by bearings and25 which are provided by. a gear housing member 26. The housin member 26is provided with finished cylin rical surfaces 27 whlch" are received bya cylindrical aperture within the frame of the engine (not shown) forthe purpose of supporting the gear housing 26. 1 I

The shaft 23 is provided with slines 28 which are drivingl connected witthe mternally-splined hu 29 of a clutch drum 30 having a c lindrical'clutching surface 31 co axial, wit the slightly tapered conlcalclutching surface 32 of a clutch cylinder 33 which is formed integrallywith the hub 34 of a pinion 35 which is movable endwise along the shaft23 into engagement with a gear 36 connected with t e engine to bestarted. The diameter of the left end of surface 32 is the same as thediameter of the 1926. Serial No. 107,110.

in the drawing, the clutching surfaces 31 and 32 will be located inalignment so as to re ceive a clutch spring 39 having the externaleriphery of its turns ground to substantialy true cylindrical form andfrictionally en ageable with the clutch drum surfaces 31 an 32. Theclutch members are maintained in assembled relation by a wire split ring40 which lsrecelved bya groove in the clutch member 30.

The clutch and pinion are moved endwise along the shaft 23 meansincluding a lever which is pivota 1y mounted upon a rod 51 supported bythe gear housing 26. The lower end of the lever is. bifurcated toprovide arms 52, each of which carries a stud or roller 53 received bythe groove 54 which is defined by flanges 55 and 56 of a sleeve 57slidable along the shaft 23. The sleeve 57 is attached by riveting orswedging at 58 to the inwardly-extending flange 59 of a tube 60 havingan outwardly-extending flange 61 which is received by a tube 63. Thetube 63 has an inwardlyextending flange 62 adapted to engage the flange61 in order to prevent se aration of t e sleeve 57 from the clutch.' hetube 63 provides an internal annular groove 64 for receiving anoutwardly-extending annular flange 46 rovided by' the clutch member 30.The fiimge 46 is defined by an end face of the member 30 and an annulargroove 47 in member 30. The oove 64 is defined by a shoulder 65 preormed in the tube 63 before assembling, and by an edge portion 66 whichis forced intothe groove 47 after assembling. In order to transmitmotion yieldingly from the sleeve 57 to the clutch, a spring 69 islocated between the flan e 59 and the clutch drum 30, the right-han endof the spring being received by, an end face of the member 30. The hub29 is encircled by the spring .69 and spaces one end of it from theshaft 23.

The lever 50 is operated by a pedal. rod 70 which extends through a cupmember 71 mounted upon the floor-board 72 of an automotive vehicle. Therod is provided with a pedal 73,'and a spring 74i5 located between thecup 71 and the pedal 73 for the purpose of maintaining the startingapparatus in the position shown in the drawa in order to close theswitch and to cause the motor to crank the engine through the clutch andgearing described.

The clutch spring 39 is coiled in such a manner that when the shaft 28is rotated in engine cranking direction, the spring 39 will expand toincrease the frictional grip against the clutch drums, in order totransmit the torque required to crank the engine.

The spring 39-is initially cylindrically-helical, and its externaldiameter is slightly greater than the diameter ofthe drum surface 31.When the spring is assembled within the clutch drums it will engage thedrum surface 31 with relatively slight unit pressilre, but the conicaldrum surface 32 will be engaged by the spring with greater unit pressurethan exerted within the surface 31.

This effect is due to the fact that the width of the surface of contactof each spring coil engaging the drum surface 31 is the width of thecylindrically helical surface with which the spring is initiallyprovided, whereas the width of the surface of contact of each springcoil engaging the conical drum surface 32 is much narrower than thewidth of each coiltheoretically a helical line contact.

Furthermore the tot-a1 pressure normally exerted by the coils againstthe conical surface '32 is greater than the total pressure exerted bythe coils against the surface 31, since the former coils are wedginglyengaged by the conical surface 32 and are therefore contracted bythe'surfaoe 32 increasingly pro-- ceeding toward the right-hand end ofthe spring, as viewed in the drawin The right end turn of the spring 39will'exert the greatest pressure since it is contracted to the greatestdegree.

When the shaft 28 begins to turn in the engine cranking direction, thespring coils against the drum 30 will be' frictionally dragged ahead 'ofthe coils within the drum 33, sincethe pinion 35 is held stationary bythe engine gear '36 and the spring coils within drum 33 tend to remainstationary due to relatively great friction between these coils and thedrum 33. Engine crankin rotation of the shaft 28 tends to. unwind thespring 39 and to cause itto expand about the clutch drums to the extentthat the pressure 'overrunning,

creased sufliclently to transmit cranking the spring upon the drum 30sufliciently to I permit the spring to overrun the drum 30. Thus theinion35 will'freely overrun the motor sha t- 23 and the motor will notbe rotated at an excessive speed after the engine .becomesself-operative.

The coils which are located within the drum 30 are required. to gripdrivingly and to overrun the drum 30. The total initial pressure mustnot be so great as to prevent et this pressure must be intorque. Theseconditions require the use of a certain number of turns of the spring toengage the drum 30. The turns within the drum 33 are not required tooverrun said drum but only frictionally to grip it with pressure whichis initially suflicient to anchor .one end of the spring to the drum 33,and

with pressure which is finally suflicient to Therefore ;the

transmit cranking torque. number of spring turns re uired to engage thedrum 33 may be less t an the number of turns required to engage the drum30, because the total spring pressure .exerted by the spring upon thedrum 33 is subjected to less variationthan the total spring pressureexerted by the spring upon the drum 30. Another reason why. the numberof turns within the drum 33 can be less than the number of turns withinthe drum 30 is because the coefficientof friction between the turnsagainst the drum 33 is greater than the coeflicient of friction betweenthe turns against the drum 30. In-order that the clutch may overrun, thesurface 31 must .be lubricated.

Ill)

This cannot be done practicall without also lubricating the surface 32.ince the unit pressure exerted by those coils-within the surface 32, isgreater than the unit pressure exerted b those coils within the surface31, there wil be less lubricant betweenthe surface 32 and the springthan between the surface 31 and the spring. Hence the coefiicient offriction between the spring and surface 32 will be greater than betweenthe spring and surface 31, particularly since the oil-,film be tween thespring and surface 32 may be de-" stro ed. v

e result of this construction and arrangement is that the clutch may ,bemade shorter and with less material than a s rin clutch having bothclutch drums cylin rica It is of course obvious that the drums could theconical drum could be sphned to the .lever 50 to the clutch member bythe spring 69 so that the motor switch 21 ma be closed prior to meshingthe pinion wit the engine gear 36 in case the pinion teeth abut theengine gear teeth before the pinion is meshed. I

After the engine becomes self-operative, the operator may release thepedal 7 3 whereupon the spring 74 will cause the lever 50 to moveclockwise into the position shown in the drawing. The pinion 35 will bewithdrawn from engagement with the engine gear 36 by a non-yieldingdevice which includes the tubular arts 63 and 60 which cooperate throught e engagement of their respective flanges 62 and 61. v

The clutch s ring 39 may be caused to grip the clutch rum 30 sooner ifits end portion 39 is bent slightly outwardly from the outer shown 1nFig. 2. v

While the form of embodiment of the present-invention as hereindisclosed, constitutes a preferred form, it is to be under-, stood thatother forms might be adopted, all comin within the scope of the claimswhich fol ow.

What is claimed is as follows:

1. En 'ne starting apparatus, comprising in combl n ation, a motor, ashaft operated by the motor, a clutch member drivmgly connected with theshaft and slidable a ong the shaft, a clutch member slidable along theshaft. and rotatable independently thereof, saidclutch members havingcoaxial friction surfaces, a helical-coil spring adapted to frictionallyenga e said-surfaces an to provide a one-way driving connection betweensaid members, a pinion slidable alon the shaft and connected with thesecond c utch member, means for preventing separation of said clutchmembers while rm-ltting. relative rotationof said mem rs, means for,yieldingly moving the clutch members and pinion in a direction to meshthe pinion with an enginegear and includng a sleeve slidable along theshaft and a spring surrounding the shaft and located between the sleeveand first clutch member, and means for non-yieldingly withdrawing thepinion from the engine gear and including said i sleeve and two telescoically coacting tubular parts enclosin e second mentioned spring, onepart being attached to said sleeve periphery of the clutch spring as andthe other to said first clutch member, said tubular vparts hav coactinflanges limiting se aration of sai sleeve om'said clutch mem rs.

2. Engine starting a'p aratus according? fiist clutch member to claim 1,in which the is provided with an outwardly' rojecting annular flangedefined by an annu ar groove adjacent one end face of said clutchmemher, and in which one of said tubular-parts is attached to saidclutch member byproviding said tubular part with an internal annulargroove for receiving said flange of the clutch member, said groove beindefined by a shoulder formed internally of t e tubular part and by anedge portion of said part which is forced into the annular grooveof sailgrst clutch member. i d1 ngine startin a ratus accor 'n to claim 1, inwhich the fii g 1s provided with a hub which is encircled Iydsaid secondspring for the purpose speci- 4. En ine starting apparatus com risin incomb mation, a motor a shaft ogerate d" by the motor, a pinion adaptedto engage a gear connected with the engine to be started, and a one-waclutch for connecting the shaft to the pinlon and including abutting.

from a diameter equal to that of the cy stclutch member 00 drical andtheother is conical and ta ers drical clutch surface to a slightly lessdiameter, and a coiledspring normally -in frictional engagement with thedrums and'wedgingly engaged by the conical surface, said :gr bem free ofutch rum.

5. Engine starting ap inratus such as dey fined by claim 4 in who thewidth of the surface of contact between the sprin and the conicalsurface isless than the wi th of the surface of contact between thespring and the cylindrical surface for the purpose specified.

6. Engine starting apparatus such as defined by claim 4 in WhlC thespring is provided initially with an external clutch drum engagingsurface which is c lindricall -helicla1 and of sulbftnlntial widt thesur ace of tesprin w 'c iswe g1 enaedb the conica surface being fi e ssinwl d thah the width of said cylindrically-helical clutch drum engagingsurface.

In testimony whereof I hereto aflix my signature GEORGE w. ELSEY.

positive connection with Ill

